Grips for a Model 70S

"Vintage Gun Grips" has the "flat" grips for the Model 70S, but they say that they have a "large" size which is 1/16" taller than the "small" size. I have measured the right panel on mine, and I come up with a measurement halfway in-between. My pistol is a 1981-vintage Berben .380. Anybody know which size grip I should get?